The present invention relates to a liquid sensing sensor and an apparatus for sensing leakage of body fluid using the same.
Recently, in developed countries, a decrease in birthrate and an increase in elderly population have proceeded with increasing speed and the problem of caring for the aged has become a social problem. In Japan, although various administrative efforts have been made upon forecasting the near future, they are insufficient yet so that it is an exigent task to make a society that is comfortable for elderly people to live in.
Under these circumstances, in facilities where a large number of aged persons who are bedridden or suffering from senile dementia are cared for, man-power on the side of the care provider and the facility remain to be maintained sufficiently yet and workers therein are forced to work hard. The same situation will exist in the case of caring for patients with a heavy handicap.
One of the causes for such heavy work is an exchange of diapers. The reason is that aged persons and patients are heavier in body weight than babies and heavy physical work is required for the exchange of diapers. Besides, many of those aged persons or patients who need diapers cannot recognize excretion by themselves or cannot inform of excretion and hence it is necessary to make patrols day and night to check it. In particular, aged persons have low anabiotic ability of the skin or the like so that other problems such as skin diseases will arise if excrement is left untreated for a long time. Accordingly, patrols have to be made frequently.
If there is a means which enables caregivers to immediately know that excretion has occurred, the above-described problem will be alleviated. Some conventional means are introduced in Kaoru Nishimura: xe2x80x9cCare for incontinencexe2x80x9d published by Chuo Hoki Shuppan (First edition 5th print, Dec. 1, 1992). These include a sensor having electrodes whose tips are separated from each other. The sensor is inserted between the body and the diaper and an apparatus for sensing incontinence connected to the sensor is attached to or arranged near the person under care. When excreted urine flows between the electrodes, current flows due to ionizing components such as salts contained in urine to activate the sensing apparatus and inform of the excretion by means of a buzzer or the like.
However, the apparatus for sensing incontinence has the following problems.
(1) Sensors once used must be subjected to treatment such as washing or sterilization before they can be utilized again. This has a contrary effect of requiring cost and labor.
(2) With the sensor having the above structure, a certain amount of urine must flow to the position of the sensor. However, with recent development of a paper diaper, most of the excreted urine is quickly absorbed in the inside of the diaper. As a result, sometimes the sensor cannot sense excretion when it has actually occurred.
(3) Both the sensing apparatus and sensor sometimes do not work normally, causing problems in the wearable state because of the movement of the person under care.
(4) Although it is by nature sufficient that only the caregiver knows of an excretion, information means such as a buzzer let others know it so that the person under care will feel nervous when the buzzer sounds.
Under the circumstances, the present invention has been made and it is an object of the present invention to provide a body fluid leakage sensing apparatus that is downsized so as to be adapted to any state of wearing and that accurately informs only the caregiver, and a liquid sensing sensor that is applied to the body fluid leakage sensing apparatus and senses a small amount of body fluid with high sensitivity and can be thrown away.
For this purpose, according to the present invention, a liquid sensing sensor comprises a water absorber made of a porous material having high electric resistance provided on a head of the sensor, at least two electrodes having respective tips arranged separate from each other through the water absorber but fixed to the water absorber respectively, and a coating means for covering the water absorber and the tips. That is, even a small amount of body fluid is allowed to permeate into the inside of a porous material from its exposed portion to thereby reduce the resistance between the electrodes due to ionization components, so that the liquid can be recognized.
A body fluid leakage sensing apparatus using the sensor comprises a sensor that is made of a liquid-permeable porous material and that changes its electric resistance by permeation of a body fluid into the inside thereof, a comparative circuit that is connected with the sensor and senses the leakage of body fluid by a change in the resistance, a transmitter circuit that sends body fluid leakage information from the comparative circuit to a communicator means, and a power source for initiating respective circuits.
Further, a body fluid leakage sensing apparatus comprising a sensor-side transmitter-receiver wearable on the body by a person who has a possibility of leaking body fluid and a communicator-side transmitter-receiver for wireless monitoring of the sensor-side transmitter-receiver, is characterized in that the sensor-side transmitter-receiver comprises a battery, a sensor that is made of a liquid permeable porous material and that changes its electric resistance by permeation of a body fluid into the inside thereof, a command receiving means for receiving a command from the communicator-side transmitter-receiver, a judgment means for measuring a resistance value of the sensor by the command, comparing the resistance value with a predetermined value, and judging a presence or absence of leakage of body fluid, and a data transmitting means for transmitting data obtained by the judgment means to the communicator-side transmitter-receiver, and is further characterized in that the communicator-side transmitter-receiver comprises a power source, a command transmitting means for transmitting the command to the sensor-side transmitter-receiver, a data receiving means for receiving the data from the sensor-side transmitter-receiver, a notifying means for notifying of the presence or absence of the leakage of body fluid, a recording means for recording the presence of the leakage of body fluid, a judgment means for judging the received data and actuating the notifying means and the recording means, whereby a presence or absence of the leakage of body fluid by wireless is monitored.
Accordingly, when a leakage of body fluid is sensed by the above-described sensor, the comparative circuit judges whether or not the change sensed is leakage of body fluid by a change in resistance and if a judgment is made that the leakage of body fluid is present, then the comparator circuit produces a signal and transmits the signal from the transmitter circuit to the notifying means outside, thereby notifying a third party of the leakage.